Abstract

Since the discovery that Endamoeba histolytica is widely distributed throughout the human population in temperate as well as in tropical countries, both extensive and intensive surveys of the protozoa of the human intestinal track have been made in representative areas of Europe, America and Eastern Asia. In general these surveys have indicated that active trophozoites of E. histolytica are more commonly found in the passed stools of residents of warm climates, while examination of similar specimens in the more temperate areas has shown a marked preponderance of cysts. In many of the latter cases no history of symptoms has been evoked so that the question of the “carrier” case has been a serious one which the clinician has had to face.

The identification of either the trophozoite or the cyst of Endamoeba histolytica requires a differentiation of this species from E. coli and E. nana, as well as from Iodamoeba and the rare species Dientamoeba fragilis.